Method and apparatus for cooling cement clinker

ABSTRACT

Method and apparatus for cooling a rotary kiln product, for example cement clinker, by means of atmospheric air caused to flow countercurrently to the clinker through cooling tubes rotating with and provided in planetary fashion around the outlet end of the rotary kiln in which the clinker is manufactured, and connected with the kiln through substantially radial chutes through which the clinker passes into the tubes, additional outside air being introduced directly into the cooler tubes.

United States Patent [151 3,704,873 Jensen 1 Dec. 5, 1972 {54] METHOD AND APPARATUS FOR 3,512,764 5/1970 Jensen ..263/32 R COOLING CEMENT CLINKER [72] Inventor: Flemming Edvin Jensen, Primary J'Camby Copenhagemvalby, Denmark Attorney-Dean S. Edmonds et a1.

[73] Assignee: F. L. Smidth & Co., Cresskill, NJ. 1 7 ABSTRACT [22] Flled: 1971 Method and apparatus for cooling a rotary kiln [2]] Appl. No.: 172,857 product, for example cement clinker, by means of atmosphe ric air caused to flow countercurrently to the [30] Foreign Application priority Data clinker through cooling tubes rotating with and provided in planetary fashion around the outlet end of the Sept 9 Great Bmam "42808/70 rotary kiln in which the clinker is manufactured, and {52] U S 263/32 C 34/135 connected with the kiln through substantially radial 51 1 niecll ..F2 7b 7/38 chutes thmughwhich the linker Passes into the tubes 5 Field of Search R, 32 1 4/ 5 7 additional outside air being introduced directly into i the cooler tubes. [56] References Cited Luther ..34/1 35 X 9Claims, 8 Drawing Figures PATENTED DEC 5 I972 SHEET 2 0F 3 FIG. 4

FIG. 3

FIG. 5

INVENTOR. FLEMMING E. J'ENSEN j/w ATTORNEYS BY M 5 a,

METHOD AND APPARATUS FOR COOLING CEMENT CLINKER I BACKGROUND OF THE INVENTION most of the clinker slides down the chute while this is inclined at an angle to the vertical.

The clinker reaching the end of the kiln is often sticky on account of its high temperature. and partly molten condition. It does not slide smoothly down the inclined chutes. Although these are made fairly wide so as to reduce the air velocity through them, sticky clinker may stick to their walls and partly clog the chutes, and in extreme cases they may even become blocked. Stickiness of the clinker presents the further disadvantage that on reaching a cooling tube it may collect in heaps instead of passing smoothly along the tube in counter-current to the cooling air.

The chutes together with the clinker inlet ends of the tubes are exposed to intense heat, so that for durability they have to be made of very expensive materials.

SUMMARY OF THE INVENTION According to the invention such drawbacks are relieved by introducing, in addition to the amount of air taken in through the clinker outlet of each cooler tube, an additional amount of atmospheric air through one or more openings provided in the wall of the cooler tube.

The additional air may be introduced into the cooler tube through several openings which may be uniformly distributed throughout its length, but may preferably be introduced exclusively at or near the clinker inlet end of the cooler tube.

By thus intensifying the cooling action exerted by the cooling air near the clinker inlet, the effect of the undesirable stickiness of the clinker is largely removed, because the partly molten surfaces of the clinker which give rise to this stickiness solidify, and the individual pieces of clinkcr become surrounded by non-sticky crusts. This in turn improves the movement of the clinker through the chutes and through the clinker inlet ends ofthe tubes.

As a result, it becomes possible either to use less expensive materials in these parts of the cooling system or to obtain a longer life with the use of the same materials.

A further result obtained is an air-quenching of the clinker, which in certain cases has been found useful.

According to the invention the additional amount of air is preferably only introduced into the individual cooler tube essentially during such intervals in the rotation of the kiln during which clinker is passing through the chute of the cooler tube. Thus, the introduction of unnecessary cold air into the kiln itselfis avoided.

From the apparatus standpoint according to the invention a number of cooler tubes are arranged in planetary fashion around the outlet end of a rotary kiln with their axes parallel or substantially parallel to the axis of the kiln. Each cooler tube has at one end an opening constituting the inlet for cooling air and the outlet for cooled clinker. At the other end each tube has an opening which is connected with the interior of the kiln through a connecting pipe. This constitutes the chute for the entrance of hot clinker from the kiln and also the inlet to the kiln for the cooling air from the cooler tube.

A number of openings for introducing additional air are provided, preferably near the transition between the cooler tube and the chute.

Each individual opening for introducing additional air may preferably beprovided with agrate serving to prevent clinker from leaving the cooler tube through the opening.

Advantageously opening for introducing additional air may furthermore be provided with means to ensure that the opening is free during the intervals of the rotation of the kiln in which the amount of cooling air introduced through the opening has an opportunity of sweeping the clinker, while it is closed during the remaining time.

' The said means for alternately uncovering and covering the opening for introducing additional air may according to the invention consist of a weight-loaded or compulsorily controlled damper, advantageously a swivel damper.

When the construction is such that the additional air is caused to pass through clinker that has already fallen into the tube, the supply of air may be continued after the clinker has ceased to move into the tube during the rotation of the kiln, but while the air still comes into contact with clinker on the bottom of the tube.

The additional air may be simply drawn into the kiln by the suction in it, in the same way as the main cooling air passing through each tube is drawn into the kiln, or air may be forced in by a fan or otherwise. If the air is passed through clinker already on the bottom of the tube forced draught is necessary.

Thus, according to the invention the rotating kiln/cooler system may be equipped with fans, preferably one for each cooler tube, adapted to force cooling air through the opening or openings for additional air, preferably through an outer casing.

The invention will now be described in detail with reference to the drawings.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS FIG. 1 is a view partly in vertical section and partly in elevation showing the lower or right end portion of a rotary kiln having planetary cooler tubes mounted thereon.

FIG. 2 shows diagrammatically a vertical longitudinal section of the parts adjacent. to the clinker chute for one of the cooler tubes of FIG. 1 with a single opening for introducing additional air arranged near the clinker inlet end of the cooler tube.

FIG. 3 shows an embodiment corresponding to that shown in FIG. 1, but with a grate before the opening.

FIG. 4 shows an embodiment with a single opening for introducing additional air and with a weight-loaded swivel damper.

FIG. 5 shows diagrammatically a cross-section taken on the line 5-5 of FIG. 4.

FIG. 6 shows diagrammatically a vertical longitudinal section of the parts adjacent to a clinker chute for a rotary kiln planetary cooler according to the invention with a single opening for introducing additional air and with a fan mounted on the cooler tube.

FIG. 7 shows a corresponding section with air introduced by the action of a fan through a perforated plate section and FIG. 8 shows a section taken on the line 8-8 of FIG.

DETAILED DESCRIPTION In FIG. 1 there is shown the lower end portion of a rotary kiln shell 1 which in this instance is provided with a refractory lining. Arranged in planetary fashion and equally spaced around the circumference of shell 1 there are numerous cooler tubes 2, only the uppermost and lowermost of which are illustrated. The axes of these cooler tubes are parallel to the axis of kiln shell 1 and the entrance of the clinker into tubes 2 is through a series of inlet openings 2b. Connected with each of these openings is a pipe forming a chute 3 which is connected to a cooler tube 2 near its-right end. The lower end of kiln shell 1 is permanently closed by an end member 2f.

As the kiln tube 1 rotates the clinker moves through the openings 2b and chutes 3 into the several cooler tubes 2and works its way towards the left end of these tubes where it is discharged through outlet openings 2a into a common vertical chamber 2d which surrounds the kiln. The clinker is discharged through outlet 2e at the bottom of the chamber 211. Cooling air for the kiln is introduced through this clinker outlet 2e.

In FIGS. 26 hot clinker 4 is passing through chute 3 shortly after a cooler tube 2 has on the rotation of the kiln passed its bottom position. The movement of the cooling air drawn through the cooler tube 2 and further through the chute 3 into the kiln is indicated by arrows. The said cooling air consists partly of a main flow of air drawn into the cooler tube through its clinker outlet 2e and chamber 2d and partly of an additional flow of air drawn into the cooler tube through an opening 5, and as indicated by the arrows the said additional air unites with the main flow of cooling air on its way to the rotary kiln in or directly before the chute 3 and subjects the clinker falling or having just fallen through the chute to an air-quenching. The opening 5 is staggered somewhat in the direction of the axis of the cooler tube in order to prevent clinker from leaving the cooler tube 2 through the said opening.

FIG. 3 shows by way of example a built-in grate 6 covering the opening 5 and thus constituting another means to prevent clinker from leaving the cooler tube through the said opening. If there is such a grate, the inlet 5 need not necessarily be offset radially inwards.

FIGS. 4 and 5 show control of the air flow through the inlet 5 by dampers 7 pivoted on pins 8 which are mounted in flanges 9 on the ends of the inlets 5 and are weighted as shown at 10. As the kiln rotates openings 11 in the dampers 7 are alternately brought into and out of register with the inlets 5.

FIG. 6 shows a fan 12 mounted on the end of the cooler tube 2, there being as many fans as there are tubes. This fan operates continuously, and it may deliver some air to the cooler tube at all times. Advantageously a damper operated by gravity or a cam is provided on its suction side to cut the air delivery down to a minimum except when the supplementary air is required. Alternatively such a damper may be so arranged in a closed circuit through which the air is circulated that supplementary air flows out of this circuit into the cooler tube only when required.

With the arrangement shown in FIG. 6 only the clinker passing through the chute and falling into the tube is effectively air-quenched. FIGS. 7 and 8 show a construction in which a fan 13 delivers air into a hood 14 which surrounds part of the cooler tube. The part thus surrounded is formed as a grate with openings 15 small enough to retain pieces of clinker. This grate extends round that part of the circumference of the tube which receives the clinker and also for a little distance beyond this in the left-hand direction as seen in FIG. 8 so that air can be passed through the clinker on the bottom of the tube afterthe kiln has rotated in such a position that clinker is no longer falling through the chute.

I claim:

1. A method of cooling rotary kiln solid material by means of atmospheric air caused to flow countercurrently to the material through cooler tubes rotating with and provided in planetary fashion around the outlet end of the rotary kiln in which the material is treated, and connected with the kiln through substantially radial chutes through which the material passes into the cooler tubes, characterized in that in addition to the amount of air taken in through the solid material outlet of each cooler tube an additional amount of atmospheric air is introduced through at least one opening provided in the wall of the cooler tube.

2. A method as claimed in claim 1, characterized in that the additional air is introduced exclusively near the solid material inlet end of the cooler tube.

3. A method according to claim 2, characterized in that the additional air is introduced into the individual cooler tube only during the intervals in the rotation of the kiln during which solid material is passing through the chute of the cooler tube.

4. Apparatus for cooling solid material treated in a rotary kiln which comprises a plurality of cooler tubes arranged in planetary fashion around the outlet end of a rotary kiln with their axes parallel or substantially parallel to the axis of the kiln, each cooler tube having at one end an opening forming an inlet for cooling air and the outlet for cooled solid material, and at the other end an opening which is connected with the interior of the kiln through a chute for hot solid material from the kiln and the inlet to the kiln for the cooling air from the cooler tube, characterized in that the wall of the cooler tube is provided with at least one opening for introducing additional cooling air.

5. A cooler as claimed in claim 4, characterized in that there is only one opening for introducing additional air, provided near the junction between the cooler tube and the chute.

6. A cooler as claimed in claim 4, characterized in that each individual opening for introducing additional air is provided with a grate serving to prevent solid material from leaving the cooler tube through the opening.

7. A cooler as claimed in claim 5, characterized in that the opening for introducing additional air is provided with means to ensure that the opening is free during the intervals of the kiln rotation in which the amount of cooling air introduced through the opening has an opportunity of sweeping the solid material, while it is closed during the remaining time.

that the rotating kiln/cooler is provided with fans, advantageously one for each cooler tube, connected to force cooling air through each opening for additional air. 

1. A method of cooling rotary kiln solid material by means of atmospheric air caused to flow countercurrently to the material through cooler tubes rotating with and provided in planetary fashion around the outlet end of the rotary kiln in which the material is treated, and connected with the kiln through substantially radial chutes through which the material passes into the cooler tubes, characterized in that in addition to the amount of air taken in through the solid material outlet of each cooler tube an additional amount of atmospheric air is introduced through at least one openiNg provided in the wall of the cooler tube.
 2. A method as claimed in claim 1, characterized in that the additional air is introduced exclusively near the solid material inlet end of the cooler tube.
 3. A method according to claim 2, characterized in that the additional air is introduced into the individual cooler tube only during the intervals in the rotation of the kiln during which solid material is passing through the chute of the cooler tube.
 4. Apparatus for cooling solid material treated in a rotary kiln which comprises a plurality of cooler tubes arranged in planetary fashion around the outlet end of a rotary kiln with their axes parallel or substantially parallel to the axis of the kiln, each cooler tube having at one end an opening forming an inlet for cooling air and the outlet for cooled solid material, and at the other end an opening which is connected with the interior of the kiln through a chute for hot solid material from the kiln and the inlet to the kiln for the cooling air from the cooler tube, characterized in that the wall of the cooler tube is provided with at least one opening for introducing additional cooling air.
 5. A cooler as claimed in claim 4, characterized in that there is only one opening for introducing additional air, provided near the junction between the cooler tube and the chute.
 6. A cooler as claimed in claim 4, characterized in that each individual opening for introducing additional air is provided with a grate serving to prevent solid material from leaving the cooler tube through the opening.
 7. A cooler as claimed in claim 5, characterized in that the opening for introducing additional air is provided with means to ensure that the opening is free during the intervals of the kiln rotation in which the amount of cooling air introduced through the opening has an opportunity of sweeping the solid material, while it is closed during the remaining time.
 8. A cooler as claimed in claim 7, characterized in that the means for alternately uncovering and covering the auxiliary air opening for introducing additional air consists of a compulsorily controlled damper.
 9. A cooler as claimed in claim 4 characterized in that the rotating kiln/cooler is provided with fans, advantageously one for each cooler tube, connected to force cooling air through each opening for additional air. 